Protection of LVDC Microgrids in Grid-Connected and Islanded Modes Using Bifurcation Theory

Low-voltage dc (LVdc) microgrids facilitate the integration of renewable energy systems and modern loads. However, they suffer from lack a sensitive, selective, reliable, fast protection strategy. The low fault current high-resistance faults makes detection faulty zone identification challenging tasks for engineers. This article proposes scheme that is effective both bolted at LVdc feeders. developed strategy relies on two intelligent electronic devices ends protected zone, calculating normalized superimposed component line current. By adding this to input periodically forced harmonic oscillator (PFHO), occurrence direction can be simultaneously determined based state variable with only possible values during stable unstable modes. It eliminates need selection various thresholds different microgrid structures/topologies. proposed classify pole-to-ground pole-to-pole grid-connected islanded microgrids. reliable performance PFHO-based assessed simulation model ±750 V meshed TN-S grounding system.